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United States Patent |
5,036,532
|
Metroka
,   et al.
|
July 30, 1991
|
Portable telephone with power source/mode change during calls
Abstract
A unique cellular portable telephone (100) automatically accommodates a
power source change during a cellular telephone call between the
portable's battery (300) and another battery or an external power source
from vehicular adaptor (200), such as, for example, a battery eliminator
adaptor, a hands-free adaptor, or a mobile transceiver adaptor. The
operating mode of portable telephone (100) also automatically changes when
it is coupled to or decoupled from vehicular adaptor (200) during a
cellular telephone call. For example, when vehicular adaptor (200) is
plugged into portable telephone (100), the portable display (116) is not
disabled when inactive for a predetermined time.
Inventors:
|
Metroka; Michael P. (Algonquin, IL);
Walczak; Thomas J. (Woodstock, IL);
Krolopp; Robert K. (Hoffman Estates, IL)
|
Assignee:
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Motorola, Inc. (Schaumburg, IL)
|
Appl. No.:
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634784 |
Filed:
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December 27, 1990 |
Current U.S. Class: |
455/566; 455/127.1; 455/572 |
Intern'l Class: |
H04M 011/00; H04B 007/00 |
Field of Search: |
455/343,89,127,38,68,90
379/58,61,62,63
|
References Cited
U.S. Patent Documents
4627107 | Dec., 1986 | Hohlfeld et al. | 435/89.
|
4680787 | Jul., 1987 | Marry | 379/58.
|
4684870 | Aug., 1987 | George et al. | 320/20.
|
4852147 | Jul., 1989 | Suzuki et al. | 379/58.
|
Foreign Patent Documents |
0283235 | Nov., 1988 | JP | 455/127.
|
Primary Examiner: Eisenzopf; Reinhard J.
Assistant Examiner: Negash; Kinfe-Michael
Attorney, Agent or Firm: Hackbart; Rolland R.
Parent Case Text
This is a continuation of application Ser. No. 07/389,084, filed Aug. 3,
1989 and now abandoned.
Claims
We claim:
1. A method for controlling a radiotelephone call when changing the power
source coupled to a portable radiotelephone between internal power
sources, first external power sources, or the internal power source and
the first external power source, said portable radiotelephone having at
least first and second modes of operation when coupled to the internal
power source and the first external power source, respectively, said
method comprising the steps of:
storing, during a radiotelephone call, pre-selected information identifying
the radiotelephone call;
producing, in response to an interruption of said power source, an output
signal for a predetermined time interval; and
re-entering the radiotelephone call corresponding to said stored
pre-selected information when said power source is changed and said output
signal is present, and operating said portable radiotelephone in the first
mode of operation when said power source is changed to the internal power
source and in the second mode of operation when said power source is
changed to the external power source.
2. The method according to claim 1, wherein said portable radiotelephone
includes display means for displaying entered digits of telephone numbers
when enabled and keypad means having a plurality of keys activated for
entering corresponding digits of telephone numbers, and means for enabling
and disabling said display means, said method further including the steps
of:
during said first mode, enabling said display means when a key of said
keypad means is activated and disabling said display means when the keys
of said keypad have not been activated for a predetermined time; and
during said second mode, continuously enabling said display means.
3. The method according to claim 1, wherein said portable radiotelephone
includes an internal microphone coupled to first amplifying means when
enabled and an internal speaker coupled to second amplifying means when
enabled, and said portable radiotelephone is further adapted to be coupled
to a second external power source provided by first adaptor means
including an external microphone and an external speaker, and said
portable radiotelephone having a third mode of operation when coupled to
the second external power source, said method further including the steps
of:
during said first mode, enabling said first and second amplifying means;
and
during said third mode, disabling said first and second amplifying means.
4. A method for controlling a radiotelephone call when changing the power
source coupled to a portable radiotelephone between internal power
sources, first external power sources, or the internal power source and
the first external power source, said portable radiotelephone having at
least first and second modes of operation when coupled to the internal
power source and the first external power source, respectively, and said
portable radiotelephone including a real time clock producing an output
signal having a magnitude indicating current time, said method comprising
the steps of:
storing, during a radiotelephone call, pre-selected information identifying
the radiotelephone call;
storing the magnitude of the output signal in response to an interruption
of said power source; and
re-entering the radiotelephone call corresponding to said stored
pre-selected information when said power source is changed and the
magnitude of the output signal is less than a predetermined amount greater
than the stored magnitude of the output signal, and operating said
portable radiotelephone in the first mode of operation when said power
source is changed to the internal power source and in the second mode of
operation when said power source is changed to the external power source.
5. The method according to claim 3, wherein said portable radiotelephone
includes display means for displaying entered digits of telephone numbers
when enabled and keypad means having a plurality of keys activated for
entering corresponding digits of telephone numbers, and means for enabling
and disabling said display means, said method further including the steps
of:
during said first mode, enabling said display means when a key of said
keypad means is activated and disabling said display means when the keys
of said keypad have not been activated for a predetermined time; and
during said second mode, continuously enabling said display means.
6. The method according to claim 3, wherein said portable radiotelephone
includes an internal microphone coupled to first amplifying means when
enabled and an internal speaker coupled to second amplifying means when
enabled, and said portable radiotelephone is further adapted to be coupled
to a second external power source provided by first adaptor means
including an external microphone and an external speaker, and said
portable radiotelephone having a third mode of operation when coupled to
the second external power source, said method further including the steps
of:
during said first mode, enabling said first and second amplifying means;
and
during said third mode, disabling said first and second amplifying means.
7. A portable radiotelephone for communicating radiotelephone calls, said
portable radiotelephone having a power source which may be changed between
internal power sources, first external power sources, or the internal
power source and the first external power source, and said portable
radiotelephone having at least first and second modes of operation when
coupled to the internal power source and the first external power source,
respectively, said portable radiotelephone comprising:
timing means for producing, in response to an interruption of said power
source, an output signal for a predetermined time interval; and
control means including memory means for storing, during a radiotelephone
call, pre-selected information identifying the radiotelephone call, and
said control means re-entering the radiotelephone call corresponding to
said stored pre-selected information when said power source is changed and
said output signal is present, and operating said portable radiotelephone
in the first mode of operation when said power source is changed to the
internal power source and in the second mode of operation when said power
source is changed to the first external power source.
8. The portable radiotelephone according to claim 5, further including
display means for displaying entered digits of telephone numbers when
enabled, and keypad means having a plurality of keys activated for
entering corresponding digits of telephone numbers; said control means
enabling said display means when a key of said keypad means is activated,
disabling said display means when keys of said keypad means have not been
activated for a predetermined time, and operating said portable
radiotelephone in the first mode of operation when said power source is
changed to the internal power source; and said control means continuously
enabling said display means and operating said portable radiotelephone in
the second mode of operation when said power source is changed to the
first external power source.
9. The portable radiotelephone according to claim 7, further including an
internal microphone coupled to first amplifying means when enabled and an
internal speaker coupled to second amplifying means when enabled, and said
portable radiotelephone further being adapted to be coupled to a second
external power source provided by first adaptor means including an
external microphone and an external speaker, and said portable
radiotelephone having a third mode of operation when coupled to the second
external power source, said control means enabling said first and second
amplifying means and operating said portable radiotelephone in the first
mode of operation when said power source is changed to the internal power
source, said control means enabling said first and second amplifying means
and operating said portable radiotelephone in the second mode of operation
when said power source is changed to the first external power source, and
said control means disabling said first and second amplifying means and
operating said portable radiotelephone in the third mode of operation when
said power source is changed to the second external power source.
10. A portable radiotelephone for communicating radiotelephone calls, said
portable radiotelephone having a power source which may be changed between
internal power sources, first external power sources, or the internal
power source and the first external power source, and said portable
radiotelephone having first and second modes of operation for the internal
power source and the first external power source, respectively, said
portable radiotelephone comprising:
real time clock means coupled to a non-interruptible power source for
producing an output signal having a magnitude indicating current time; and
control means including memory means for storing, during a radiotelephone
call, pre-selected information identifying the radiotelephone call and, in
response to an interruption of said power source, the magnitude of the
output signal; and said control means re-entering the radiotelephone call
corresponding to said stored pre-selected information when said power
source is changed and the magnitude of the output signal is less than a
predetermined amount greater than the stored magnitude of the output
signal, and operating said portable radiotelephone in the first mode of
operation when said power source is changed to the internal power source
and in the second mode of operation when said power source is changed to
the first external power source.
11. The portable radiotelephone according to claim 10, further including
display means for displaying entered digits of telephone numbers when
enabled, and keypad means having a plurality of keys activated for
entering corresponding digits of telephone numbers; said control means
enabling said display means when a key of said keypad means is activated,
disabling said display means when keys of said keypad means have not been
activated for a predetermined time, and operating said portable
radiotelephone in the first mode of operation when said power source is
changed to the internal power source; and said control means continuously
enabling said display means and operating said portable radiotelephone in
the second mode of operation when said power source is changed to the
first external power source.
12. The portable radiotelephone according to claim 10, further including an
internal microphone coupled to first amplifying means when enabled and an
internal speaker coupled to second amplifying means when enabled, and said
portable radiotelephone further being adapted to be coupled to a second
external power source provided by first adaptor means including an
external microphone and an external speaker, and said portable
radiotelephone having a third mode of operation when coupled to the second
external power source, said control means enabling said first and second
amplifying means and operating said portable radiotelephone in the first
mode of operation when said power source is changed to the internal power
source, said control means enabling said first and second amplifying means
and operating said portable radiotelephone in the second mode of operation
when said power source is changed to the first external power source, and
said control means disabling said first and second amplifying means and
operating said portable radiotelephone in the third mode of operation when
said power source is changed to the second external power source.
Description
BACKGROUND OF THE INVENTION
The present invention is generally related to radiotelephones, and more
particularly to a cellular portable telephone which accommodates a power
source change and corresponding operating mode change during a
radiotelephone call.
Cellular portable telephones currently have batteries with capacity for
one-half hour of continuous operation. As a result most users typically
carry one or more spare batteries so that they can switch to another
battery when the portable telephone indicates that the battery voltage is
low. However, when the battery is removed during a cellular telephone
call, the call is terminated and the user must redial the call.
Interruption of the power source and termination of a cellular telephone
call in process also occurs when the user plugs the cellular portable
telephone into a vehicle's battery by way of a vehicular adaptor installed
therein, such as a battery eliminator connected to the vehicle's cigarette
lighter. For the foregoing reasons, there is a need for a cellular
portable telephone which accommodates a power source change and
corresponding operating mode change during a cellular telephone call.
OBJECTS OF THE INVENTION
Accordingly, it is an object of the present invention to provide a unique
portable radiotelephone, which automatically accommodates a power source
change and corresponding operating mode change during a radiotelephone
call.
It is another object of the present invention to provide a unique portable
radiotelephone, which automatically determines the type of power source
coupled thereto and changes the operating mode of the portable
radiotelephone to correspond thereto.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a cellular portable telephone 100 embodying
the present invention.
FIG. 2 is a flow chart for the power-up process used by microcomputer 104
in FIG. 1 for re-entering a cellular telephone call in progress before a
power source change.
FIG. 3 is a flow chart for the process used by microcomputer 104 in FIG. 1
for storing and updating specific cellular information during a cellular
telephone call.
FIG. 4 is a circuit diagram of timer 400 in cellular portable telephone 100
in FIG. 1.
FIG. 5 is a block diagram of a hands-free adaptor embodiment of vehicular
adaptor 200 in FIG. 1.
FIG. 6 is a block diagram of a mobile transceiver adaptor embodiment of
vehicular adaptor 200 in FIG. 1.
FIG. 7 is a block diagram of a battery eliminator adaptor embodiment of
vehicular adaptor 200 in FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, there is illustrated a block diagram of a cellular
portable telephone 100 embodying the present invention, which
automatically accommodates a power source change during a cellular
telephone call between the portable's battery 300 and another battery or
an external power source from vehicular adaptor 200, such as, for example,
a battery eliminator adaptor, a hands-free adaptor, or a mobile
transceiver adaptor. In other embodiments, vehicular adaptor 200 may be a
voltage source coupled to conventional AC line power. Portable telephone
100 includes cellular radiotelephone transceiver 102 operable in cellular
radiotelephone systems, microphone 120 and switchable amplifier 122,
speaker 124 and switchable amplifier 126, radio microcomputer 104 with
internal RAM storing pertinent cellular telephone call parameters and ROM
108 storing control software, a power controller 110 including regulators
coupled to battery 300 for generating DC voltages for powering other
blocks, a line conditioner 113 coupled to external power source 119, a
keypad/display microcomputer 114 including internal ROM with control
software for controlling display 116 for displaying entered digits of
telephone numbers when enabled and keypad 118 having keys activated for
entering corresponding digits of telephone numbers. Radio microcomputer
104, keypad/display microcomputer 114, and vehicular adaptor 200 are
coupled to and communicate with one another by way of three-wire data bus
115, which operates as described in U.S. Pat. Nos. 4,369,516 and 4,616,314
(incorporated herein by reference). Blocks 102-126 of portable telephone
100 may be conventional blocks of commercially available portable
radiotelephones, such as, for example, the "MICROTAC PT" Cellular
Telephone available from Motorola, Inc. The "MICROTAC PT" Cellular
Telephone is described in further detail in operator's manual no.
68P81150E49, published by and available from Motorola C & E Parts, 1313
East Algonquin Road, Schaumburg, Ill. 60196.
Vehicular adaptor 200 may likewise be conventional adaptors for
commercially available portable radiotelephones. In the preferred
embodiment, vehicular adaptor 200 may be a battery eliminator adaptor with
a cigarette lighter plug, a hands-free adaptor with regulated power
supply, or a mobile transceiver adaptor with regulated power supply, all
of which couple portable telephone 100 to vehicle battery 500. According
to the present invention, the operating mode of portable telephone 100
automatically changes when it is coupled to or decoupled from vehicular
adaptor 200 during a cellular telephone call. When coupled to battery 300,
portable telephone 100 is in the battery mode, in which inter alia,
display 116 is disabled by microcomputer 114 when inactive (no keys of
keypad 118 activated) for a predetermined time for minimizing battery
current drain. Display 116 is re-enabled when keys of keypad 118 are
activated to display the telephone number digit corresponding to the
activated key (see the aforementioned operator's manual no. 68P81150E49).
When coupled to battery eliminator adaptor 200, portable telephone 100 is
in the battery eliminator mode, in which, inter alia, display 116 is not
disabled when inactive for a predetermined time. When coupled to duplex
hands-free adaptor (DHFA) 200, portable telephone 100 is in the DHFA mode,
in which, inter alia, display 116 is not disabled when inactive for a
predetermined time. When coupled to mobile transceiver adaptor (CVC) 200,
portable telephone 100 is in the CVC mode, in which, inter alia, display
116 is not disabled when inactive for a predetermined time. The foregoing
modes of operation of portable telephone 100 are summarized below in Table
I.
TABLE I
______________________________________
Portable Power Display External Amplifiers
Mode Supply Timer Data Bus 122 & 126
______________________________________
Battery Internal Enabled Not used Enabled
Battery External Disabled Not used Enabled
Eliminator
Hands-Free
External Disabled CMP = Shifted
Disabled
High State
Mobile External Disabled Used Disabled
Transceiver
______________________________________
Portable telephone 100 also includes timer 400 which may be implemented by
individual components as shown in FIG. 4 or which may be a commercially
available real-time clock which has a digital output having a value
indicating the current time and is coupled via diode 427 to back-up
battery 424 providing power when battery 300 is removed. Timer 400 is
necessary to prevent attempting to re-connect a cellular telephone call
when more than a predetermined length of time has elapsed during a power
source change. In this case, the cellular telephone call should not be
re-connected since the cellular base site equipment of the cellular
radiotelephone system will terminate the call automatically on loss of the
supervisory audio tone (SAT) for a predetermined length of time and may
then re-assign the cellular radio channel and SAT to another cellular
telephone call. In most cellular radiotelephone systems, the predetermined
length of time for loss of SAT is typically greater than five seconds.
When battery 300 is removed during a cellular telephone call in order to
replace it with a fully charged battery, timer 400 produces an output
signal 414 having a binary zero state (approximately signal ground) for a
period of approximately four seconds which is shorter than the base site
loss of SAT detection (at least five seconds). If another battery 300 is
plugged into portable telephone 100 within the four second period,
cellular telephone 100 may detect the binary zero state of timer output
signal 414 and re-enter the cellular telephone call that was in process
when the discharged battery 300 was removed. If the fully charged battery
300 was not plugged in within the four second period, timer output signal
414 will have a binary one state (approximately 5 VDC) and the previous
cellular telephone call will not be re-entered. A cellular telephone call
is also re-entered after the momentary power source interruption due to
plugging and un-plugging vehicular adaptor 200, and according to the
present invention, the operating mode of portable telephone 100 also
automatically changes.
Portable telephone 100 also includes a circuit 418, 420 and 422 which
supplies standby current to RAM of radio microcomputer 104. Capacitor 418
is kept charged through resistor 420 and diode 422 to approximately +5 V
and supplies RAM of radio microcomputer 104 with standby current for at
least four seconds when battery 300 or external power source 119 is
interrupted. Diode 422 also prevents capacitor 418 from discharging into
the +5 V supply when the +5 V supply is off. Resistor 420 limits the
charging surge current applied to capacitor 418. Alternatively, back-up
battery 424 may be used to supply RAM of radio microcomputer 104 with
standby current via diode 427.
In order to re-establish a cellular telephone call after a power source
change, certain call parameters need to be stored in RAM of radio
microcomputer 104. Such call parameters include, for example and without
limitation, the present cellular channel number (corresponding to the
transmitter and receiver frequencies of cellular transceiver 102), the
present supervisory audio tone (SAT) frequency, the present transmitter
power level setting (i.e. one of eight possible levels), a call state
active flag to indicate that a call was in process prior to the power
source change, and the present user telephone number that was used to
place the call (the user may have a cellular telephone with multiple
telephone numbers). These call parameters are stored in RAM of radio
microcomputer 104.
Referring next to FIG. 2, there is illustrated a flow chart for the
power-up process used by microcomputer 104 in FIG. 1 for re-entering a
cellular telephone call in process before a power source change and
determining the new operating mode of portable telephone 100. Entering at
START block 202, the process proceeds to decision block 204, where a check
of the call state active flag (binary one=call in process) is made to
determine if a call had been in process. If not, NO branch is taken to
block 208 for executing the normal power up sequence. If a call had been
in process, YES branch is taken from decision block 204 to decision block
206, where a check is made to determine if timer output signal 414 has a
binary zero state. If not, NO branch is taken to block 208 for executing
the normal power up sequence.
If timer output signal 414 has a binary zero state, YES branch is taken
from decision block 206 to decision blocks 210, 212, 214 and 218 to
determine the new operating mode of portable telephone 100, which may be
different from the operating mode prior to the power source change.
Portable telephone 100 may be in one of four operating modes, the battery
powered mode, the battery eliminator mode, the duplex hands-free (DHFA)
mode, or the mobile transceiver (CVC) mode. At decision block 210, a check
is made to determine if portable telephone 100 is in the battery powered
mode. Microprocessor 104 detects the presence of an external power source
by monitoring the external power source signal 119 through line
conditioner 116. Line conditioner 116 may be implemented using a bipolar
NPN-type transistor having a resistor coupled from its collector to the +5
V supply, and a resistor coupled from its base to signal ground, and a
resistor coupled from its base to the external power source signal 119.
Line conditioner 116 converts the external power source signal 119 to a
binary signal 123 having a binary state indicating whether or not the
external power source 119 is present (i.e., binary zero state=external
power source 119 present).
When an vehicular adaptor 200 is plugged into portable telephone 100,
switch 128 is mechanically engaged and disconnects battery 300 from
portable telephone 100. This may be accomplished by means of a protrusion
on the connector of vehicular adaptor 200. When mechanically engaged, the
protrusion on the connector of vehicular adaptor 200 opens switch 128
which in turn disconnects battery 300. When portable telephone 100 is not
plugged into vehicular adaptor 200, switch 128 is normally closed. A diode
117 is connected between line conditioner 116 and battery 300 to prevent
battery 300 from enabling line conditioner 116 when external power source
119 is not present.
If portable telephone 100 is in the battery powered mode, YES branch is
taken from decision block 210 to block 228, where the battery powered mode
flag is set (i.e., set=binary one state). If portable telephone 100 is not
in the battery powered mode, NO branch is taken from decision block 210 to
decision block 212, where a check is made to determine if portable
telephone 100 is in the battery eliminator mode. If so, YES branch is
taken to block 226, where the battery eliminator mode flag is set. If
portable telephone 100 is not in the battery eliminator mode, NO branch is
taken from decision block 212 to decision block 214, where a check is made
to determine if portable telephone 100 is in the DHFA mode. If so, YES
branch is taken to block 224, where the DHFA mode flag is set. If portable
telephone 100 is not in the DHFA mode, NO branch is taken from decision
block 214 to decision block 218, where a check is made to determine if
portable telephone 100 is in the CVC mode. If so, YES branch is taken to
block 222, where the CVC mode flag is set. If portable telephone 100 is
not in the CVC mode, NO branch is taken from decision block 218 to block
220, where a restart is initiated.
From blocks 222, 224, 226 and 228, the process next proceeds to block 230,
where the audio paths for portable telephone 100 are set up. If portable
telephone 100 is in the battery powered mode or the battery eliminator
(see FIG. 7) mode, audio amplifiers 122 and 126 are enabled and the
transmitter (TX) audio 121 and receiver (RX) audio 125 are routed to
microphone 120 and speaker 124, respectively. If portable telephone is in
the DHFA mode, audio amplifiers 122 and 126 are disabled and the
transmitter (TX) audio 121 and receiver (RX) audio 125 are routed to the
the hands-free circuitry of vehicular adaptor 200 for processing and
coupling to the hands-free microphone 512 and speaker 510, respectively,
as shown in FIG. 5. If portable telephone is in the CVC mode, audio
amplifiers 122 and 126 are disabled and the mobile transceiver in
vehicular adaptor 200 is used, as shown in FIG. 6.
Next, at block 232, the parameters of cellular transceiver 102 are read out
of non-volatile memory (RAM) of microcomputer 104 and loaded into cellular
transceiver 102. These parameters were previously stored into RAM of
microcomputer 104 for identifying the cellular radio channel for the call
that was in process. Such parameters include, for example and without
limitation, the data which is loaded into the transmitter and receiver
synthesizers for tuning cellular transceiver 102 to the desired cellular
radio channel. Then, at block 234, the supervisory audio tone (SAT) and
the radio transmitter power level are read out of RAM of microcomputer 104
and also loaded into cellular transceiver 102. Once the cellular radio
channel, SAT and radio transmitter power level are loaded into cellular
transceiver 102, the call that was in process before the power source
change can be re-entered at block 236. Thus, by using the flow chart
illustrated in FIG. 2, it is possible to not only re-enter a call after a
power source change but also automatically change between four different
modes of operation of portable telephone 100. In other words, the user can
switch from battery operation to operation with another battery, battery
eliminator adaptor, hands-free adaptor, or mobile transceiver adaptor
automatically during a call as long as the user accomplishes the power
source change within the approximately four second time interval of timer
400.
Referring next to FIG. 3, there is illustrated a flow chart for the process
used by microcomputer 104 in FIG. 1 for storing and updating specific
cellular information during a cellular telephone call. Entering at START
block 302 during a cellular telephone call, the process proceeds to block
304, where the cellular radio channel number, SAT, present user telephone
number, and radio transmitter power level are stored in RAM of
microcomputer 104, and the call state active flag is set and likewise
stored. Next, at decision block 306, a check is made to determine if a new
cellular radio channel has been assigned to portable telephone 100. A new
cellular radio channel is assigned to portable telephone 100 when it is
handed off from one base station radio to another. Handoff typically
occurs when portable telephone 100 moves from one cell into another. If
so, YES branch is taken to block 308, where the new cellular radio channel
number is stored in RAM of microcomputer 104. From block 308 and NO branch
of decision block 306, the process proceeds to decision block 310, where a
check is made to determine if a new SAT has been assigned to portable
telephone 100. A new SAT may also be assigned to portable telephone 100
when it is handed off from one base station radio to another. If so, YES
branch is taken to block 312, where the new SAT is stored in RAM of
microcomputer 104. From block 312 and NO branch of decision block 310, the
process proceeds to decision block 314, where a check is made to determine
if a new radio transmitter power level has been assigned to portable
telephone 100. A new radio transmitter power level is assigned to portable
telephone 100 when the base station radio determines that the magnitude of
the radio frequency signal received from portable telephone 100 is either
lower than a minimum threshold or higher than a maximum threshold and
therefore needs to be adjusted. There are currently eight different power
levels for cellular telephones, of which portable telephones use six, the
two highest power levels not being used due to limitations in the output
power of portable telephones. If a new power level has been assigned, YES
branch is taken to block 316, where the new power level is stored in RAM
of microcomputer 104. From block 316 and NO branch of decision block 314,
the process proceeds to decision block 318, where a check is made to
determine if the call has been terminated. If not, No branch is taken back
to decision block 306 to repeat the foregoing process. If the call has
been terminated, YES branch is taken from decision block 318 to block 320,
where the call state flag is cleared (i.e. cleared=binary zero), and
thereafter a rescan repeating the foregoing process takes place at block
322. The flow chart of FIG. 3 is executed periodically in response to an
interrupt which sets the call state flag.
FIG. 4 is a circuit diagram of timer 400 in cellular portable telephone 100
in FIG. 1. Timer 400 includes capacitor 406 which is charged via diode 402
and resistor 404 when the TX PREKEY signal has a binary one state
(approximately 4.75 VDC). The TX PREKEY signal has a binary one state
whenever the radio transmitter of cellular transceiver 102 is enabled,
which is primarily during a cellular telephone call. By only charging
capacitor 406 when the TX PREKEY signal has a binary one state, current
drain from battery 300 is minimized. If capacitor 406 has been charged to
approximately 4.75 VDC during a cellular telephone call and battery 300 is
removed or otherwise interrupted, transistor 408 will be turned on via
resistors 410 and 412 providing a binary zero state at its output, the
timer output signal 414. The binary zero state of timer output signal 414
will be maintained for approximately four seconds based primarily upon the
values selected for capacitor 406, resistors 410 and 412 and the beta of
transistor 408. If another battery is plugged in or vehicular adaptor 200
is plugged in within the four second period, the binary zero state of the
timer output signal 414 may be detected by microcomputer 104 and the
cellular telephone call in process before the power source change may be
re-entered. If more than four seconds have elapsed, the timer output
signal 414 will have a binary one state since capacitor 406 will be
discharged to approximately signal ground turning transistor 408 off and
producing a binary one state of the timer output signal 414 via resistor
416 to +5 VDC. When timer output signal 414 has a binary one state after a
power source change, the previous cellular telephone call will not be
re-entered.
Referring to FIG. 5, there is illustrated a block diagram of a hands-free
adaptor embodiment of vehicular adaptor 200 in FIG. 1. Portable cellular
telephone 100 receives its power via external power source connection 119
which is the output of conventional voltage regulator 502. The voltage
supplied by vehicle battery 500 voltage is regulated and controlled by
voltage regulator 502. Control circuitry 504 turns regulator output 119 on
and off in response to signals from vehicle ignition 506 and data bus 115.
Data bus 115 is used by portable telephone 100 to sense if a hands-free
adaptor 200 is plugged into portable telephone 100. Receiver audio signal
125 from portable telephone 100 is coupled to amplifier 508 in hands-free
adaptor 200 to boost the level to drive speaker 510. The output from
microphone 512 is connected to portable cellular phone 100 via TX audio
connection 121 of portable telephone 100.
Referring to FIG. 6, there is illustrated a block diagram of a mobile
transceiver adaptor embodiment of vehicular adaptor 200 in FIG. 1.
Portable telephone 100 receives its power via external power source signal
119 which is the output of conventional voltage regulator 602. The voltage
supplied by vehicle battery 500 is regulated and controlled by voltage
regulator 602. Control circuitry 604 turns regulator output 119 on and off
in response to signals from vehicle ignition 606 and data bus 115. Data
bus 115 is used by portable telephone 100 to sense if a mobile transceiver
adaptor 200 is plugged into portable telephone 100. In this mode of
operation the transceiver circuitry 614 in the mobile transceiver are used
instead of cellular transceiver 102 in portable telephone 100, which is
turned off. This configuration allows for improved system performance
(i.e. higher TX power and better RX sensitivity). Transmit and receive
audio for the mobile transceiver 614 can be coupled to either the TX audio
signal 121 and RX audio signal 125 of portable telephone 100 or the
hands-free microphone 612 and speaker 610 under control of control
circuitry 604 and data bus 115.
Mobile transceiver adaptor 200 may be a conventional cellular transceiver,
and in the preferred embodiment is the transceiver of the cellular
telephone available from Motorola, Inc., and described in Motorola user's
manual no. 68P81116E58-B, entitled "DYNATAC 6000XL Cellular Mobile
Telephone User's Manual", published by and available from Motorola C & E
Parts, 1313 East Algonquin Road, Schaumburg, Ill. 60196.
Referring to FIG. 7, there is illustrated a block diagram of a battery
eliminator adaptor embodiment of vehicular adaptor 200 in FIG. 1. Portable
telephone 100 receives its power via external power source connection 119
which is the output of conventional voltage regulator 702. The voltage
supplied by vehicle battery 500 is regulated by voltage regulator 702.
In summary, a unique portable radiotelephone, has been described which
automatically accommodates a power source change between the portable's
battery and another battery or a vehicular adaptor coupled to an external
battery during a cellular telephone call. In addition, the portable
radiotelephone of the present invention also automatically changes between
four different modes of operation in response to a power source change
during a cellular telephone call.
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